What are some of the rules about the Internet that were taught to you but are now completely ignored?
For me, it was that the Internet never forgets and that you should never enter your real name. In my opinion, both of these rules are now completely ignored.
The same people who warned us about the dangers of the internet and not to believe everything, are now the ones readily falling for and spreading conspiracies and lies from social media.
this one goes both ways, if someone is doxing you, it'll be online FOUR FUCKING EVER, but if it was a cool website/funny meme/ good software, it's probably on somebody's downloads folder, but it can easily disappear and you'll never see it again.
Basic forum etiquette. It's horrifying at work seeing teams "teams" (forums) used like chats, all the cross-posting and thread necromancy, people completely unable to keep topics confined to the appropriate sub-forum, etc
Then: Don't download applications and run executables you don't fully trust.
Now: Download everyone's new snazzy app just because and scan everything with your phone that contains all your most private information so you can unlock a surprise!
I learned as a kid playing star craft that there are noobs and newbs. Newbs are people new to a game who need help learning. And a noob is someone who has played for a while and refuses to learn and would rather troll.
As in real life, it's pretty sound advice to ignore, block or otherwise disengage from trolls and other forms of belligerents. Even in the '90s when I first started using the internet, the phrase of the day was "don't feed the trolls". But people just can't help themselves. They will even reply saying "I know you're a troll, but...".
The Steam forums are a great example, where every other thread is a fake "is this game woke??" screed. The fact that you can be rewarded for being a cunt there with jesters (which translate into points that can be spent to buy profile items) just makes it a thousand times worse. You get 'paid' to be a troll on Steam. It's insanity.
The only anti-troll weapon that works or is needed is oblivion. Let their steaming turd of a post curdle in solitude. Don't even downvote it. Being downvoted is a victory for them, an acknowledgement that they exist and that they've gotten your attention and that they've annoyed you. Shadowban them from your mind. Block them so that no future posts of theirs will infect your screen. Report them so mods can remove/ban them. Just don't engage directly with the post or the user. Don't say "blocked and reported" in the troll's thread/post. Just do it silently.
On the Internet I grew up on, pretty much anything was ok except to discuss (or even speculate about) the real-world identities of users who didn't very openly disclose them.
Social media killed online aliases and I have a hard time deciding if we're all worse for it.
Instinctively I still stick by that, though, as you can tell by my anonymous profile with no bio, but when I volunteer any amount of personal info these days people are often confused that I'm not sharing openly who I am or where I'm from. Every time someone does that it weirds me out because in the 90s telling (and asking) people those things would have been such a suspicious, sketchy move.
I'm a faithful follower of never using your real name in social parts of the internet. We don't need to know and we don't want to know. The only ones who would want to know are scammers or people wanting to give you a shitty time. I only use my real name online for people and places in where it's required like talking to agents from my bank, insurance .etc And very few friends know my real name through FB and the circle anyways.
Don't send nudes online to anybody. I know of some communities where people happily are flaunting it one moment then they make a post later whining about them being exploited or that they thought they were crafty hiding the nudes from someone they're married with. They delete it but they're too naive to think that what's already out there, has most likely been saved by hundreds by now, so you're fucked either way.
Another is, is that if you want to be understood, then you need to use proper spelling and grammar. I miss the days when you got kicked at because you used 'u' in replacement of 'you'. It's just two fucking extra letters you lazy asshole. These days saying stupid shit like; 'yah fr u tha fam' is somehow a complete sentence. No, I'm going to give you shit for it and if you want me to bother caring with what you have to say, fucking make some sense. I don't even get offended by insults when they're poorly spelled, it just tells me what kind of an inept moron you are.
Sticking around and "lurking" for a bit before you try to engage with a new community, to learn the local etiquette before you make an ass of yourself. Or at least reading the rules as a bare minimum.
"Greater Internet Fuckwad Theory" was both a lie (typically invoked to defend/justify bigotry, bullying, and such) and it also served to normalize people being assholes on the internet. "Perfectly well adjusted wholesome ordinary people chant nazi slogans when they log onto the internet, for real guys! It says nothing about their character as people because for some magical reason the internet totally has no connections to lived human experiences!"
I'm glad that the so-called rule fell out of use and the excuse rings very hollow for most people now. Also, I noticed that many "ironic asshole" comedians and entertainers from the "le epic trolling" era wound up being actual assholes that hurt people outside of the act. "Million Dollar Extreme" and Justin Roiland come to mind.